Percutaneous Venopulmonary Extracorporeal Membrane Oxygenation as Bridge to Lung Transplantation

Mechanical circulatory support (MCS) as a bridge to lung transplant is an infrequent but accepted pathway in patients who have refractory end-stage pulmonary failure. The American Association of Thoracic Surgeons Expert Consensus Guidelines, published in 2023, recommends venovenous (VV) extracorporeal membrane oxygenation (ECMO) as the initial configuration for those patients who have failed conventional medical therapy, including mechanical ventilation, while waiting for lung transplantation and needing MCS. Alternatively, venoarterial (VA) ECMO can be used in patients with acute right ventricular failure, hemodynamic instability, or refractory respiratory failure. With the advancement in percutaneous venopulmonary (VP) ECMO cannulation techniques, this option is becoming an attractive configuration as bridge to lung transplantation. This configuration enhances stability of the right ventricle, prevents recirculation with direct introduction of pulmonary artery oxygenation, and promotes hemodynamic stability during mobility, rehabilitation, and sedation-weaning trials before lung transplantation. Here, we present a case series of eight percutaneous VP ECMO as bridge to lung transplant with all patients mobilized, awake, and successfully transplanted with survival to hospital discharge.

Intracannula Thrombus Formation Associated With Dual Lumen ProtekDuo Cannula in Extracorporeal Membrane Oxygenation (ECMO)

Extracorporeal membrane oxygenation (ECMO) is used in cases of severe respiratory failure refractory to medical management. Use of ECMO is increasing, along with new cannulation strategies including oxygenated right ventricular assist devices (oxy-RVADs). Multiple dual lumen cannulas are now available, which increase the potential for patient mobility and decrease the number of vascular access sites. However, dual lumen, single cannula flow can be limited by adequate inflow, requiring the need for an additional inflow cannula to meet patient demands. This cannula configuration may result in differential flows in the inflow and outflow limbs and altered flow dynamics, increasing the risk of intracannula thrombus. We describe a series of four patients treated with oxy-RVAD for COVID-19-associated respiratory failure complicated by dual lumen ProtekDuo intracannula thrombus.

Oxygenated right ventricular assist device as part of veno-venopulmonary extracorporeal membrane oxygenation to support the right ventricle and pulmonary vasculature

COVID-19 infection can lead to severe acute respiratory distress syndrome (ARDS), right ventricular (RV) failure and pulmonary hypertension. Venovenous extracorporeal membrane oxygenation (V-V ECMO) has been used for patients with refractory hypoxemia. More recently dual-lumen right atrium to pulmonary artery oxygenated right ventricular assist devices (Oxy-RVAD) have been utilized in the severe medical refractory COVID ARDS setting. Historically, animal data has demonstrated that high continuous non-pulsatile RVAD flows, leading to unregulated and unprotected circulation through the pulmonary vessels is associated with an increased risk of pulmonary hemorrhage and increased amount of extravascular lung water. These risks are heightened in the setting of ARDS with fragile capillaries, left ventricular (LV) diastolic failure, COVID cardiomyopathy, and anticoagulation. Concurrently, due to infection, tachycardia, and refractory hypoxemia, high V-V ECMO flows to match high cardiac output are often necessary to maintain systemic oxygenation. Increase in cardiac output without a concurrent increase in VV ECMO flow will result in a higher fraction of deoxygenated blood returning to the right heart and therefore resulting in hypoxemia. Several groups have suggested using a RVAD only strategy in COVID ARDS; however, this exposes the patients to the risk of pulmonary hemorrhage. We present one of the first known cases using an RV mechanical support, partial flow pulmonary circulation, oxygenated Veno-venopulmonary (V-VP) strategy resulting in RV recovery, total renal recovery, awake rehabilitation, and recovery.

A Case Series of Devastating Intracranial Hemorrhage During Venovenous Extracorporeal Membrane Oxygenation for COVID-19

OBJECTIVE

Anticoagulation may be a challenge in coronavirus disease 2019 (COVID-19) extracorporeal membrane oxygenation due to endothelial injury and dysregulation of coagulation, which may increase the risk of thrombotic and bleeding complications. This report was created to describe the authors' single institutional experience, with emphasis on the high rate of intracranial hemorrhage for the first 10 patients with COVID-19 placed on venovenous extracorporeal membrane oxygenation (VV ECMO).

DESIGN

Case series, retrospective analysis.

SETTING

Single institution.

PARTICIPANTS

Ten patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient characteristics, mortality, stroke rate, and length of stay data were collected in all patients. In addition, laboratory values of D-dimer and C-reactive protein and standard measurements of prothrombin and activated partial thromboplastin time were collected on all patients. Ten patients, each confirmed with COVID-19 via reverse transcription-polymerase chain reaction, were supported on VV ECMO for acute respiratory distress syndrome (ARDS) for a mean duration of 9.4 ± 7 days. Four of 10 patients had hemorrhagic strokes, 3 of which resulted in death. At 30 days after initiation of VV ECMO, a total of 7 survivors included 6 patients discharged from the hospital and 1 patient who remained in the intensive care unit.

CONCLUSIONS

In this small study of 10 patients, intracranial hemorrhage was a common complication, resulting in a high rate of death. The authors urge caution in the anticoagulation management of VV ECMO for patients with severe ARDS and COVID-19 patients. Close monitoring of all hematologic parameters is recommended during ECMO support while awaiting larger, multicenter studies to examine the best practice.

Acute Respiratory Failure Managed via Inter-Facility Transport for Extracorporeal Life Support: A 3-Year Experience

OBJECTIVES

The objectives of this study were as follows: (1) to describe a successful design for a mobile lung rescue program, focusing on challenges and resources required to support such a program, and (2) report short-term outcomes for patients placed on venovenous extracorporeal life support (VV-ECLS) by a transferring team before inter-facility transport to a specialized extracorporeal life support (ECLS) center.

DESIGN

This retrospective review and analysis used patient chart review to collect outcomes data and resource demand.

SETTING

A single institutional experience in an academic center in the United States.

PARTICIPANTS

Patient selection targeted the 75 patients who were placed on VV-ECLS for acute respiratory failure at an outside institution by the authors' team before transport from January 1, 2015, through December 31, 2017.

INTERVENTIONS

No intervention was made.

MEASUREMENTS AND MAIN RESULTS

Average time for dispatch and transfer was 4 hours and 10 minutes for ground and 3 hours and 30 minutes for air transport (p = 0.029). Demand was highest in winter, with 61% (46/75) of patients presenting from November through April, and daytime, with 73% (55/75) occurring from 8 am to 8 pm. Demand increased during the study period, with 21 patients in 2015, 24 in 2016, and 30 in 2017. Mortality was low, with 72% of patients surviving to discharge.

CONCLUSIONS

Herein a successful mobile lung rescue program for transfer to a regional ECLS center is described. These findings demonstrate bed availability during high census and presence of a physician for duration of transport. These challenges can be overcome and successful implementation can be made with low mortality, supporting the development of regional ECLS centers.

Veno-Venous Extracorporeal Life Support in Hemodynamically Unstable Patients With ARDS

When clinicians consider extracorporeal life support (ECLS) for acute respiratory distress syndrome (ARDS) patients with hemodynamic instability, both veno-arterial (VA) and veno-venous (VV) ECLS are therapeutic possibilities. We analyzed 17 patients with ARDS on inotropic or vasopressor support requiring ECLS for refractory hypoxemia. After implementing VV ECLS, pressor requirements (based on norepinephrine equivalents) were significantly lower in all patients (P = .0001 for overall comparison across time points). None of the 17 patients required conversion from VV ECLS to VA ECLS (95% confidence interval 0%-20.0%). In this sample of 17 patients with substantial baseline vasopressor support and hypoxemic respiratory failure, initiation of VV ECLS was associated with reduced pressor requirements. Such a strategy may help avoid complications of VA ECLS in patients with both respiratory and hemodynamic failure.

The year in cardiothoracic and vascular anesthesia: selected highlights from 2013

This article reviewed selected research highlights of 2013 that pertain to the specialty of cardiothoracic and vascular anesthesia. The first major theme is the commemoration of the sixtieth anniversary of the first successful cardiac surgical procedure with cardiopulmonary bypass conducted by Dr Gibbon. This major milestone revolutionized the practice of cardiovascular surgery and invigorated a paradigm of mechanical platforms for contemporary perioperative cardiovascular practice. Dr Kolff was also a leading contributor in this area because of his important contributions to the refinement of cardiopulmonary bypass and mechanical ventricular assistance. The second major theme is the diffusion of echocardiography throughout perioperative practice. There are now guidelines and training pathways to guide its generalization into everyday practice. The third major theme is the paradigm shift in perioperative fluid management. Recent large randomized trials suggest that fluids are drugs that require a precise prescription with respect to type, dose, and duration. The final theme is patient safety in the cardiac perioperative environment. A recent expert scientific statement has focused attention on this issue because most perioperative errors are preventable. It is likely that clinical research in this area will blossom because this is a major opportunity for improvement in our specialty. The patient care processes identified in these research highlights will further improve perioperative outcomes for our patients.

The functional aortic annulus in the 3D era: focus on transcatheter aortic valve replacement for the perioperative echocardiographer

The functional aortic annulus represents a sound clinical framework for understanding the components of the aortic root complex. Recent three-dimensional imaging analysis has demonstrated that the aortic annulus frequently is elliptical rather than circular. Comprehensive three-dimensional quantification of this aortic annular geometry by transesophageal echocardiography and/or multidetector computed tomography is essential to guide precise prosthesis sizing in transcatheter aortic valve replacement to minimize paravalvular leak for optimal clinical outcome. Furthermore, three-dimensional transesophageal echocardiography accurately can quantify additional parameters of the functional aortic annulus such as coronary height for complete sizing profiles for all valve types in transcatheter aortic valve replacement. Although it is maturing rapidly as a clinical imaging modality, its role in transcatheter aortic valve replacement is seen best as complementary to multidetector computed tomography in a multidisciplinary heart team model.

Minimally invasive mitral valve surgery utilizing heart port technology

OBJECTIVE

To determine operative outcomes of right mini-thoracotomy mitral valve surgery utilizing port access technology in first-time and reoperative cardiac surgery patients.

METHODS

From 2002 to 2011, 881 patients underwent minimally invasive mitral valve surgery. Of these, 154 patients had previous cardiac operations via sternotomy (Group 1), of which 18 (12%) had two previous operations. Seven hundred and twenty-seven patients had no previous cardiac operations (Group 2).

RESULTS

Patient demographics were similar in both groups. In Group 1, 76 (49%) patients had previous coronary artery bypass grafting, 13 (8%) had previous aortic valve surgery, and 57 (37%) had previous mitral valve surgery. Preoperative echo findings for Groups 1 and 2 included severe mitral regurgitation (MR) (88%, n = 135; 94%, n = 687), mitral stenosis (MS) (4%, n = 6; 2%, n = 12), MS + MR (8%, n = 13; 4%, n = 28), and ejection fraction (48%, 56%). Operative procedures in Groups 1 and 2 were MV repair (54%, n = 84; 89%, n = 645) and MV replacement (46%, n = 70; 11%, n = 82). Circulatory management techniques for Groups 1 and 2 included endoballoon (75%, n = 116; 79%, n = 576), Chitwood clamp (8%, n = 12; 20%, n = 147), and fibrillatory arrest (17%, n = 30; 0.5%, n = 4). Perioperative outcomes were: stroke: 2.5%, 1.6%; reoperation for bleeding: 5%, 6%; valvular reoperation rate: 0.6%, 2%; aortic dissection: 2.5%, 1%; and wound infection: 0%, 0%. Transfusion requirement was 49% (n = 76) and 31% (n = 232), respectively. Median hospital stay was seven and seven days, respectively. On postoperative echocardiography, 98% (n = 151) and 99% (n = 718) of patients had zero or trace MR (1+) with 100% freedom from MR > 2+. In-hospital mortality was 3% (n = 5) and 1% (n = 8).

CONCLUSIONS

Operative outcomes with minimally invasive mitral valve surgery utilizing port access technology can be performed safely. Stroke rate was higher in the reoperative cases (p = NS) although similar to reports evaluating redo sternotomy in mitral valve cases.

Validation study of Doppler-derived transmitral valve gradients compared to near simultaneously obtained directly measured catheter gradients immediately after mitral valve repair surgery

OBJECTIVE

To evaluate the accuracy of Doppler-derived transmitral valve gradients immediately after mitral valve repair by comparing them with near simultaneously obtained direct catheter gradients.

DESIGN

A prospective study.

SETTING

A tertiary care medical center.

PARTICIPANTS

Twenty elective adult surgical patients presenting for mitral valve repair surgery.

METHODS

Mitral valve surgery proceeded in standard fashion except for the use of a smaller than usual left ventricular vent catheter (Medtronic DLP 10 French left heart vent catheter). After completion of the mitral valve repair and subsequent cardiac de-airing, the patient was weaned from cardiopulmonary bypass. Immediately after separation, the study period began. Near simultaneous transmitral Doppler gradients were obtained with directly measured catheter gradients via the vent catheter.

RESULTS

While the mean peak gradient difference of 1.1 mmHg was small (p-value 0.18, 95% CI: -0.54 to 2.73 mmHg), the correlation between Doppler and catheter gradient measurements (Pearson correlation coefficient r = 0.54, p = 0.055) only approached statistical significance due to the large variance associated with the small sample size. In all patients with a peak gradient greater than 10 mmHg (4 of the 20 patients), overestimation of catheter gradients by Doppler occurred, with two showing a 62% to 73% discrepancy. In these two cases, there was also evidence for elevated left ventricular end-diastolic pressure (LVEDP) along with high transmitral blood flow velocities.

CONCLUSION

Doppler-derived transmitral gradients provide a simple, safe, and reliable measure of the true physiologic transmitral valve gradient. At the same time, it is important to recognize that significant Doppler over-estimation of catheter gradients may occur in patients with elevated Doppler transmitral velocities. The causes of these overestimations are unknown. They may be related to technical recording errors. They may also be related to an inherent weakness in Doppler technology--its inability to account for any distal recovery of pressure, which in a select group of patients could be significant.

Comparison of transesophageal echocardiographic analysis and circulating biomarker expression profile in calcific aortic valve disease

BACKGROUND AND AIM OF THE STUDY

Aortic valve sclerosis (AVSc), the early asymptomatic stage of calcific aortic valve disease (CAVD), is characterized by a progressive thickening of the aortic cusps without obstruction of the left ventricular outflow. In spite of its high prevalence, there are no molecular markers to characterize the early stages of CAVD before it progresses to a severe, symptomatic stage of aortic valve stenosis (AVS). The study aim was to identify any correlation between circulating biomarkers and transesophageal echocardiography (TEE) evaluation.

METHODS

A total of 330 patients with various degrees of CAVD was enrolled into the study. Blood was collected from each patient prior to surgery, and analyzed using ELISA kits following the manufacturers' instructions.

RESULTS

Significantly higher plasma osteopontin (OPN) levels were observed in AVSc patients (72.7 +/- 1.8 ng/ml; p < 0.001) and AVS patients (64.3 +/- 5.1 ng/ml; p < 0.001) when compared to controls (30.3 +/- 1.8 ng/ml). Parathyroid hormone (PTH) levels in AVSc and AVS patients (164.1 +/- 16.5 and 134.3 +/- 14.6 pg/ml; p < 0.001 and p = 0.04, respectively) were also significantly higher than in controls (61.8 +/- 4.92 pg/ml). Upon further analysis, plasma levels of OPN (p < 0.001) and PTH (p < 0.001) were found to be significantly higher in asymptomatic AVSc patients, even before calcium deposition was detected on TEE evaluation. Fetuin-A levels were lower at all stages of CAVD when compared to controls (p < 0.001 and p < or = 0.05, respectively), but were comparable among the patient groups. NT-proBNP levels were significantly higher in AVS patients than in controls (p < or = 0.01).

CONCLUSION

Serum levels of OPN, PTH, and fetuin-A showed a significant association with different stages of CAVD, with variations in their levels occurring before calcium nodules are visualized during TEE evaluation. The study results may help not only to provide a better understanding of the progression of CAVD but also to develop new tools that can be used to stage these patients.

Anesthetic considerations during minimally invasive mitral valve surgery

Advances in instruments and visualization tools as well as circulatory systems for cardiopulmonary bypass during the late 1990s have stimulated widespread adoption of minimally invasive mitral valve surgery (MIMVS). Today, MIMVS is the standard approach for many surgeons and institutions. There are multiple benefits of MIMVS. Patient satisfaction and improved cosmesis are important. Additionally, studies have consistently shown faster recovery times and less associated pain with MIMVS. Statistically significant improvement in bleeding, transfusion, incidence of atrial fibrillation, and time to resumption of normal activities with MIMVS has also been shown when comparing MIMVS with conventional mitral surgery. Most important, these benefits have been achieved without sacrificing perioperative safety or durability of surgical repair. Although a steep learning curve still exists given the high level of case complexity, continued development fueled by increasing patient demand may allow for even further expansion in the use of minimal invasive techniques.

Analysis of osteopontin levels for the identification of asymptomatic patients with calcific aortic valve disease

BACKGROUND

Calcific aortic valve disease (CAVD) is the most common cause of acquired valve disease. Initial phases of CAVD include thickening of the cusps, whereas advanced stages are associated with biomineralization and reduction of the aortic valve area. These conditions are known as aortic valve sclerosis (AVSc) and aortic valve stenosis (AVS), respectively. Because of its asymptomatic presentation, little is known about the molecular determinants of AVSc. The aim of this study was to correlate plasma and tissue osteopontin (OPN) levels with echocardiographic evaluation for the identification of asymptomatic patients at risk for CAVD. In addition, our aim was to analyze the differential expression and biological function of OPN splicing variants as biomarkers of early and late stages of CAVD.

METHODS

From January 2010 to February 2011, 310 patients were enrolled in the study. Patients were divided into 3 groups based on transesophageal echocardiographic (TEE) evaluation: controls (56 patients), AVSc (90 patients), and AVS (164 patients). Plasma and tissue OPN levels were measured by immunohistochemical evaluation, enzyme-linked immunosorbent assay (ELISA), and real-time quantitative polymerase chain reaction (qPCR).

RESULTS

Patients with AVSc and AVS have higher OPN levels compared with controls. OPN levels are elevated in asymptomatic patients with AVSc with no appearance of calcification during TEE evaluation. OPN splicing variants OPN-a, OPN-b, and OPN-c are differentially expressed during CAVD progression and are able to inhibit biomineralization in a cell-based biomineralization assay.

CONCLUSIONS

The analysis of the differential expression of OPN splicing variants during CAVD may help in developing diagnostic and risk stratification tools to follow the progression of asymptomatic aortic valve degeneration.

Balloon-assisted deployment prevents endograft misalignment during hybrid aortic arch repair

Misaligned deployment refers to eccentric flaring of the bare stent portion of the endograft that causes proximal device retroflexion resulting in suboptimal graft placement. A 71-year-old woman with 6.8-cm distal aortic arch aneurysm underwent hybrid repair with combination of open aortic arch debranching and subsequent thoracic endovascular aortic repair. During endograft deployment, misaligned opening occurred; this was corrected by using a balloon-assisted graft deployment. Follow up imaging continues to demonstrate complete aneurysm exclusion. Misaligned deployment is a clinical challenge; we hereby present a previously undescribed technique to accommodate this limitation of the current endograft technology.

The Fontan circulation and right parietal craniotomy for seizures: the challenges of adult congenital heart disease

The management of a patient who had previously undergone surgical palliation of tricuspid atresia at the age of two, and who required right parietal craniotomy for resection of seizure focus, is presented. The anesthetic considerations in patients with Fontan physiology are also presented, as well as the impact on patients undergoing neurosurgical procedures, specifically, craniotomy for seizure focus resection. The physiologic demands of modern surgical practice requires that there is a thorough understanding of the complex circulations that exist in patients with congenital heart disease.

A randomized controlled clinical trial of real-time needle-guided ultrasound for internal jugular venous cannulation in a large university anesthesia department

OBJECTIVE

The purpose of this study was to evaluate needle-guided ultrasound for internal jugular venous cannulation in a large university anesthesia department, to determine cumulative cannulation success by method, to determine first-pass cannulation success by method and operator, and to determine arterial puncture by method and operator.

STUDY DESIGN

Prospective, observational, and randomized. Blinding was not possible. Cohort size was calculated for 80% power to detect a technique difference, with significance defined as p < 0.05.

SETTING

Operating rooms of the Hospital of the University of Pennsylvania.

PARTICIPANTS

Elective surgical patients requiring internal jugular venous cannulation.

INTERVENTIONS

Cannulation of the internal jugular vein occurred by needle-guided ultrasound (NGU) or by ultrasound without a needle guide.

MAIN RESULTS

Four hundred thirty-four procedures were studied in 429 patients. NGU significantly enhances cannulation success after first (68.9%-80.9%, p = 0.0054) and second (80.0%-93.1%, p = 0.0001) needle passes. Cumulative cannulation success by the seventh needle pass is 100%, regardless of technique. The needle-guide specifically improves first-pass success in the junior operator (65.6%-79.8%, p = 0.0144). Arterial puncture averages 4.2%, regardless of technique (p > 0.05) or operator (p > 0.05).

CONCLUSIONS

Although the needle guide facilitates prompt cannulation with ultrasound in the novice operator, it offers no additional protection against arterial puncture. This may be because of a lack of control of needle depth rather than needle direction. A possible solution may be biplanar ultrasound for central venous cannulation.